Weak-Fluctuation-Induced Clutter Covariance and Subspace Structure in Single-Snapshot FDA-MIMO GPR

TL;DR

This paper investigates how weak constitutive fluctuations in dispersive media affect clutter covariance and subspace structure in single-snapshot FDA-MIMO GPR, providing a medium-aware model and propagation framework.

Contribution

It introduces a statistical propagation chain linking medium perturbations to electromagnetic and spectral observation structures, focusing on clutter effects.

Findings

Medium-induced clutter reshapes eigenspectrum and target-clutter overlap.

Spatial correlation length and scene variation significantly influence covariance structure.

FDA frequency increment alters normalized covariance geometry.

Abstract

Weak constitutive fluctuations in dispersive subsurface media can induce distributed clutter that reshapes the observation structure of ground-penetrating radar (GPR). This paper analyzes this effect for single-snapshot frequency-diverse array multiple-input multiple-output GPR. Focusing on medium-induced clutter, rather than on general target--clutter joint modeling, it establishes a statistical propagation chain from Cole--Cole parameter perturbations to electromagnetic contrast, first-order Born channel snapshots, clutter covariance, and subspace descriptors. A medium-aware snapshot model and a covariance propagation framework are then derived to characterize how constitutive uncertainty alters observation-domain spectral structure under a local weak-fluctuation regime. Numerical experiments verify the consistency of the proposed propagation relation under the adopted first-order Born and constitutive-linearization approximations. Within the tested setting, medium-induced clutter reshapes the eigenspectrum and changes target--clutter overlap metrics. Spatial correlation length and background-scene variation act as consistently strong structural drivers, while the FDA frequency increment also produces measurable changes in the normalized covariance geometry.